Whenever you want something to happen when your selection in Maya changes, the first thing that comes into your mind might be Maya ScriptJobs. However I find them very slow and not reliable, especially since they are wrapped in mel. Better use a callback from OpenMaya’s messaging system. This is how you do it: You will have to create a function that is called every time the selection changes. Make it run fast and with lots of error checking to avoid making your tool too slow. In your function, get the selection and evaluate what you want to do with it. The function could look something like this:
from maya import OpenMaya
#function to execute when selection changes
def maya_selection_changed(*args, **kwargs):
sel = OpenMaya.MSelectionList()
selection_iter = OpenMaya.MItSelectionList(sel)
obj = OpenMaya.MObject()
# Loop though iterator objects
while not selection_iter.isDone():
# Now we can do anything with each of selected objects.
# In this example lets just print path to iterating objects.
dagPath = OpenMaya.MDagPath.getAPathTo(obj)
except RuntimeError, err:
Don’t worry, you don’t have to use maya API but you can use pymel or even maya.cmds instead. In my example I just print the names of the selected nodes however I would avoid any prints as they are slowing down […]